The thing on the maglite LED upgrades is to be careful you are getting the newest ones that are up to date in technology and you made your upgrade worth the cash you're putting out.
The LEDs outputs have been following Moore's law in the past decade or so, doubling efficiency over and over again.
Given this fact, you may also want to reconsider if you need a 2D flashlight to lug around. It would be like someone using an old Brick Cellphones just for nostalgia's sake.
Something just slightly bigger than the 2AA mini-mag using 18650 batteries will provide you overwhelming light when you need it, or "regular" usable walking around light that matched your 2AA regular incandescent for 40hours
I would suggest to take a look at Fenix lights, they are well made with no overly complexities as some LED flashlights may have.